Improvement in the manufacture of butt and bilge bolts



F. Tunai-:v Y Manufacture of --utfand Bilge sans.

UNITED STATES PATENT OEEIGEo FRANCIS B. TORREY, OF BATH, MAINE.

IMPROVEMENT IN THE MANUFACTURE OF BUTT AND BILGE BOLTS.

Spcciiication forming part of Letters Patent No. 152,194, dated June 16,1874 application filed May 23, 1874.

To all whom it may concern Be it known that I, FRANCIS B. TORRES', ofBath, Maine, have invented certain new and useful Improvement in theManufacture of Butt and Bilge Bolts for ship-building purposes, of whichthe following is a specilication: L

Bolts for the above purpose' have been usually made of wrought metal;but many are now using a cast bolt,because of its comparative cheapness,and for other reasons not necessary to enumerate. Much ditticulty,however, is experienced in using the latter bolt, for, if made of acomposition or mixture hard enough to admit of the bolt being readilydriven without bending', it is aptto be too brittle and poorly adaptedfor clinchin g or upsetting. If, on the other hand, it is made of a softmixture or composition, it will not drive well, but is very liable tobend and break down.

In order to obviate all these objections, and to produce a compositionbolt that will drive well without liability of breaking during thatoperation, and that will at the same readily clinch after being thusdriven, I make the bolt of a comparatively soft mixture or composition,and then impart to this bolt the requisite stiffness to make it drivewell without impairing its clinching properties, by cold-hammering orcompressing the Sallie, so as to give it a surface hardness. I thusproduce a coldhammered or compressed composition bolt, which isadmirably adapted for the use for which it is designed, combining initself all the good qualities of both the soft andthe hard compositionbolts,witho\1t any of the defects of either, and fully equal in quality'to a wrought bolt, while costing much less than the latter.

I make my improved bolt mostly of a composition of copper and zinc, say,in the proportion of t-wo of the former metal to 011e of the latter, andI sometimes add a little tin and lead to the mixture. From thiscomposition the bolts are made by casting in the usual way.

I would remark here.7 however, that while I specify the composition Iprefer to use, I do not limit myself to that special composition, sinceany ordinary or suitable compound metal or alloy adapted to ship-building purposes, and having the requisitesoftness or malleableproperties, may be employed.

The bolt made as above described is too soft and yielding to bepractically available for use, and in order to complete it I condenseit, and give it a surface hardening, by compressing, swaging, or coldhammering itprocesses well known in the art, and readily understoodwithout further explanation. After this process the bolt is completed,and is ready for use.

I have devised the bolt with special reference to the requirements ofshipbuilding, but it can, of course, be used for other purposes.

The drawing hereto annexed represents one style of nished bolt made inaccordance with my invention.

Having now described my invention, and the manner in which the same isor may be carried into effect, what I claim, and desire to secure byLetters Patent, is-

rIhe mode described of manufacturingbolts for ship-building and otherpurposes by casting the same from a suitable soft metallic compound oralloy, and then condensing and surface -hardening it by the compressingor coldhammering opera tion.

In testimony whereof I have hereunto signed my name.

FRANCIS B. TORREY.

lVitnesses:

W. D. MUssENDEN, GEO. SNELL.

